1. Field of the Invention
The present invention relates to a light emitting device, particularly to the light emitting device which includes a heat dissipative board, a wiring board adhering to and fixed to the heat dissipative board, a light-emitting element mounted on the heat dissipative board, and a bonding wire connecting the light-emitting element and the wiring board.
2. Description of the Related Art
JP-A-2007-109701 discloses a board for mounting a light-emitting element having a structure of bonding a wiring plate and a support member. In the wiring plate, a through-hole, for causing reflected light by the support member on which a light-emitting element is mounted, to be transmitted is formed. The light-emitting element is mounted on the support member just under the through-hole.
JP-A-2011-009298 discloses a light-emitting diode light source device which includes a base, an insulating plate, and a plurality of light-emitting diode elements. The base has thermal conductivity. The insulating plate has a surface on which a conductive pattern is formed, and is fixed to a surface of the base. The plurality of light-emitting diode elements is mounted on a mounting area of the surface of the base, which is exposed by a through-hole provided in the insulating plate.
JP-A-2009-182307 discloses a manufacturing method of a light-emitting element in which a light-emitting element is mounted on a board having conductor wiring, the light-emitting element and the conductor wiring are electrically connected to each other by using a conductive wire, and the light-reflecting resin is provided so as to bury a portion of the conductive wire when the light-reflecting resin is provided on the board so as to cause the light-reflecting resin which reflects light from the light-emitting element to surround the light-emitting element. Thus, absorption of light is suppressed by exposing the conductive wire as little as possible.
In the technology of JP-A-2007-109701, since a side surface of the light-emitting element faces an inner peripheral wall surface of the through-hole of the wiring plate, light emitted from the side surface side of the light-emitting element is absorbed by the surface of the inner peripheral wall of the through-hole of the wiring plate, and thus there is a problem in that light extraction efficiency is degraded.
In the technology of JP-A-2011-009298, since a side surface of the light-emitting diode element faces an inner peripheral wall surface of the through-hole of the insulating plate, light emitted from the side surface side of the light-emitting element is absorbed by the surface of the inner peripheral wall of the through-hole of the insulating plate, and thus there is a problem in that light extraction efficiency is degraded.
In the technology of JP-A-2009-182307, if a synthetic resin material having a low thermal expansion coefficient is used as light-reflecting resin, when the light-reflecting resin is heated by heat emitted from the light-emitting element, thermal stress of the light-reflecting resin is applied to the conductive wire (bonding wire) buried in the light-reflecting resin, and thus there is a problem in that the conductive wire is easily cut off.